Migrate org.mockito.Matchers#any* to org.mockito.ArgumentMatchers

The former is deprecated and replaced by the latter in Mockito 2. However, there is a
functional difference: ArgumentMatchers will reject `null` and check the type
if the matcher specified a type (e.g. `any(Class)` or `anyInt()`). `any()` will
remain to accept anything.

For more information see []

Tested:
    TAP --sample ran all affected tests and none failed
    []

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=250690285

javatests/google/registry/tools/GenerateAllocationTokensCommandTest.java

@@ -48,7 +48,7 @@ import javax.annotation.Nullable;
 import org.joda.time.DateTime;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.Mockito;
+import org.mockito.ArgumentMatchers;
 
 /** Unit tests for {@link GenerateAllocationTokensCommand}. */
 public class GenerateAllocationTokensCommandTest
@@ -93,7 +93,7 @@ public class GenerateAllocationTokensCommandTest
         .doThrow(fakeException)
         .doCallRealMethod()
         .when(spyCommand)
-        .saveTokens(Mockito.any());
+        .saveTokens(ArgumentMatchers.any());
     runCommand("--number", "1");
     assertAllocationTokens(createToken("123456789ABCDEFG", null, null));
     assertInStdout("123456789ABCDEFG");